In the area of all stabilizers such as antioxidants, UV absorbers, light stabilizers and the like, the original stabilizers are often simple, relatively inexpensive molecules involving some warhead moiety. As particular end-use application and new polymer substrates become important, molecular adjustments to these original stabilizers are made to meet the new requirements.
An example of this is seen in U.S. Pat. No. 4,713,475 where some original hindered phenolic antioxidant molecules are modified to contain long chain ester moieties for combatibility and solubility considerations in new substrates.
There have been some attempts to put long chain alkyl ester moieties on benzotriazole UV absorbers as seen in U.S. Pat. No. 5,705,474 which describe fabric softeners where one component is a benzotriazole UV absorber substituted by an alkyl ester of 1 to 22 carbon atoms. No long chain ester is specifically described or exemplified in this reference.
European Patent Application 315,155 A2 describes some negative type silver halide photographic material which contain development accelerators which are inter alia benzotriazoles substituted on the benzo ring by dialkylaminoalkyl amide groups. None of these materials are UV absorbers and are clearly structurally different from the instant compounds. Likewise, U.S. Pat. No. 4,778,728 describes some benzotriazole corrosion inhibitors which are structurally very different from the instant compounds.
WO 97/42261 describes amide functional UV absorbers which resist blooming and migration which are inter alia benzotriazole UV absorbers substituted on the phenyl ring by—CONH-alkyl amide moieties having up to 18 carbon atoms in the alkyl chain. The instant long chain alkyl ester or amide compounds do not overlap with these amide compounds. Indeed, the instant compounds have 25–100 carbon atoms for each alkyl group.
U.S. Pat. Nos. 4,853,471, 4,973,702 and 5,032,498 describe benzotriazole UV absorbers substituted on the phenyl ring by long chain alkyl ester moieties of up to 18 carbon atoms which can be interrupted by —O— and/or substituted by OH.
U.S. Pat. Nos. 5,280,124 and 5,977,219 and copending application Ser. No. 09/234,880 describe benzotriazole UV absorbers substituted on the phenyl ring by long chain alkyl ester groups of up to 24 carbon atoms and on the benzo ring with electron withdrawing groups in the 5-position. When the instant compounds are unsubstituted on the benzo ring, the phenyl ring can be substituted by long chain alkyl ester groups of 20 to 100 carbon atoms.
Additionally, the instant compounds are useful in protecting candles from discoloration.
Candles have been known for many centuries going back to the eighth century B.C. The nature of candles is described in Ullmann's Encyclopedia of Industrial Chemistry, Volume A5 at pages 29–30 where it is seen that candles are made from paraffin, beeswax and stearin as basic materials, and where a host of additives may also be present.
It is not surprising that with candles and wax becoming increasingly more important attention was paid as to how to stabilize said materials. At the National Candle Association Meeting in Houston, 1994, R. van der Vennet presented a paper on “Antioxidants in Wax—Replacement of BHT” touting the use of Vitamin E (tocopherol) as an antioxidant to prevent the yellowing of wax when oxidized. WO 94/13736 describes the same invention.
EP 359,488 A3 and EP 133,964 B1 describe stabilized waxes used in cosmetics where the waxes are the same or similar to those used in candles.
EP 5,922 A1 describes lip cosmetics where the waxes are useful in lipsticks and are related to those useful in candles.
U.S. Pat. No. 5,879,694 describes in detail transparent gel candles both in composition and structure. The use of BHT as an antioxidant is mentioned.
At the National Candle Association Technical Meeting on Apr. 16, 1998, F. A. Ballentine et al., presented a paper entitled “Inhibiting Color Fading of Dyed Candles with CYASORB® Light Absorbers” in which the general theories of thermal oxidation and photodegradation are discussed along with data on the effect of light absorbers on color stability of dyed candle waxes. The light absorbers compared are 4-octyloxy-2-hydroxybenzophenone UV-531; 4-methoxy-2-hydroxybenzophenone UV-9; 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole UV-5365; 2-(2-hydroxy-5-tert-octylphenyl-2H-benzotriazole UV-5411 and 2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole UV-2337).
U.S. Pat. No. 5,964,905 teaches dyed and scented candle gels containing triblock copolymers and a hydrocarbon oil of high flash point. This reference teaches that a light (UV) absorber may be used to improve the shelf stability of the candle color when exposed to visible or ultraviolet light. Two preferred absorbers are ethylhexyl p-methoxycinnamate (PARSOL® MCX, Roche) and 2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole (CYASORB® 5411, Cytec).